IBM 90nm G5 chip to ‘outrun’ Prescott, Athlon 64

Best Desktop Processor award winner

IBM's technically as yet unannounced PowerPC 970FX has won the Microprocessor Report Analysts' Choice Award for Best Desktop Processor.

And according to MR editor-in-chief Peter Glaskowsky, Intel and AMD had better watch out.

The 970FX is the 90nm die-shrink of the original 130nm PowerPC 970, launched back in October 2002 and finally shipped last summer, most notably inside Apple's Power Mac G5.

IBM is expected to launch the 970FX formally next week at the IEEE Solid-State Circuits Conference (ISSCC), along with its PowerTune technology, which adds SpeedStep-style clock frequency scaling that can synchronise across multiple processors.

The chip should be shipping very shortly. Apple's Xserve G5, which is based on the 970FX, is due to ship this month.

IBM documentation has already revealed the 970FX's impressive power characteristics: 24.5W at 2GHz. The 130nm 970, by contrast, eats up 51W at 1.8GHz.

That will help 970FX-based machines scale very well against Intel's 90nm offering, Prescott. "The 970FX should yield well at 2.5GHz, up from the 2GHz speed of the 970 used in Apple's Power Mac G5," writes Glaskowsky. "This 25 per cent increase in clock rate will not soon be matched by Intel or AMD. Prescott is struggling to eke out minor clock-rate improvements, and AMD will need to wait for its own 90nm products - due in H2 - to achieve substantial speedups for Athlon 64.

Glaskowsky also believes Apple will be able to get the part up to 3GHz by the summer - a promise made by CEO Steve Jobs last year. "That's an aggressive target," Glaskowsky notes, "but it should be achievable. The 970FX has the necessary architectural sophistication in its deep pipelines to make this speed possible, and IBM has the necessary technology in its CMOS 10S process.

"At 3GHz, the 970FX should outrun the chips we expect from AMD and Intel in the same time frame."

But the story doesn't just centre on clock speed. Because the 970FX is a die-shrink, it should come in at just over half the size of the 118mm², says Glaskowsky. The upshot is that IBM should be able to punch rather more 970FXs out of a 300mm wafer than Intel can produce 112mm² Prescotts. AMD is still on 200mm wafers and will be until 2006.

That yields IBM "a large cost advantage" over Intel Prescott, says Glaskowsky, which bodes well for Apple's ability to balance margins against system cost going forward. ®